Steam-engine.



R. C. STEVENS.

, STEAM ENGINE.

APPLICATION man JAN. 5. 1915.

Patented Oct. 19, 1915.

ROBERT C. STEVENS, 0F ERIE, PENNSYLVANIA, ASSIGNOR TO SKINNER ENGINE COMPANY, OF ERIE, PENNSYLVANIA, A CORPORATION.

STEAM-ENGINE.

Specification of Letters Patent.

Patented Oct. 19, 1915.

Application filed January 5, 1915. Serial No. 550.

To all whom it may concern Be it known that I, ROBERT CISTEVENS, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvements in Steam-Engines, of which the following is a specification.

This invention relates to steam engines of the uniflow kind, that is in which steam is admitted through inlet ports at the end or ends ofthe cylinder and exhausted through a separate exhaust port or ports uncovered provide means for delayin when desired,

the point of the beginning 0 compression by the closure of the auxiliary exhaust ports, or in other Words, increasing the period'of exhaust through the auxiliary ports beyond what has heretofore been permitted by the piston covering the same.

Another object of the invention is to enable the auxiliary exhaust ports to be placed farther from the ends of the cylinder, so that the cool exhaust vapor is not pushed back so near the cylinder heads.

In the embodiment of the invention herein shown and described these objects are effected by making notches or recesses in the faces of the piston, which register with the auxiliary ports when desired, as when running non-condensing, but not with the middle or main exhaust ports. However, when de sired, as when the engine is to be run condensing, the piston and its rod can be turned within the cylinder a sufiicient amount to throw the notches out of register withthe auxiliary exhaust ports, whileat the same time they continue to be out of register with the main exhaust ports.

In the drawings, Figure 1 is a longitudinal section on the line 1-1 of Fig. 2, of part of a cylinder and piston provided \with the invention. Fig. 2 is a section on the line a 22 of Fig. 1, showing the notches in the piston in register with the auxiliary exhaust ports. Fig. 3 is a similar view showing the piston turned, with the 'notches out of register with said ports.

A represents the cylinder barrel; B the piston therein; D the middle or main exhaust ports; (3- the auxiliary exhaust ports in the cylinder wall between the cylinder heads and the middle exhaust ports.

E are circumferentially spaced cut outs or notches in the faces of the piston, at the edges thereof, adapted to register with the auxiliary ports C but so located as not to register with the main ports-D, which therefore are located out of longitudinal alinement with the ports C. The reason for this is, that the ports D shall remain covered on the power stroke until they are cleared by the normal edge of the piston and consequently not shorten the expansion or power period or vary the point of release or exhaust of steam from the cylinder.

The passages from the ports C to the exhaust chamber and pipe are controlled as usual by valves F which may be operated by any suitable means and in a known manner to close said passages during the expansion period and open the same during the exhaust period. These valves F are shown simply for illustration and another type of valve or valves may be used for the purpose stated.

In operation, it will be seen that on the return or exhaust stroke, the point at which compression begins is delayed until the inner Wall of the notches or recesses E passes over the ports C, when the piston closes said ports and compression begins. This is advantageous when running non-condensing, as there is less vapor trapped in the cylinder, and the ports C can be placed farther from the cylinder heads than would otherwise be possible, which improves steam consumption by avoiding the forcing of the cool exhaust vapor at the middle part of the cylinder so near to the cylinder ends, the cooling of which, it is recognized, should be avoided.

when it is desired to run condensing, the pistonv and rod can be turned within the cylinder sufliciently to throw the notches out of register with the auxiliary ports C, as

' shown in Fig. 3, while at the same time the increased compression is, in consequence, desirable, the piston and rod may be turned in the same way.

WV hat I claim as new is 1. In a steam engine, the combination of a cylinder having a main exhaust port, and an auxiliary exhaust port between said port and the end of the cylinder, and a piston 1n the cylinder adapted to open and close said ports, said piston being shortened at a point in alinement with said auxlliary exhaust port.

2. In a steam engine, the combination of a cylinder having a main exhaust port, and

an auxiliary exhaust port between said port and the end of the cylinder, and a piston in the cylinder adapted to open and close said ports, said piston having a recess in the face thereof in position to register with the said auxiliary port, to delay the point of closure thereof.

. 3. In a steam engine, the combination of I said ports, said piston having a recess in the face thereof in position to register with the said auxiliary port and to not register with the said main port.

5. Ina steam engine, the combination of a cylinder having a main exhaust port, and an auxiliary exhaust port between said port and the end of the cylinder, said ports being out of longitudinal alinement, and a piston in the cylinder adapted to open and close said ports, said piston having a recess in the face thereof in position to register with the said auxiliary port and to not register with the said main port, and also insuch position that the piston may be turned to not register said recess with either of said ports.

6. In a steam engine, the combination of a cylinder having a main exhaust port, and an auxiliary port in the cylinder wall between said port and the end of the cylinder, and a piston in the cylinder adapted to open and close said ports, said piston having a passage therein extending from the face thereof to the periphery thereof in position to register with the said auxiliary port.

In testimony whereof, I aflix my signature in presence of two witnesses.

ROBERT C. STEVENS.

Witnesses:

B. C. OLsoN, HARRY G. ADAM. 

